(This post was updated and expanded on May 3, 2017.)

With the C.E.O. of Exxon Mobil now officially nominated for Secretary of State, the oil and gas giant is being cast as a kinder and gentler fossil fuel behemoth. Here’s the New York Times editorial board’s weekend take:

[Rex] Tillerson assumed the role of chairman and chief executive of Exxon Mobil in January 2006, and during his tenure the company acknowledged, for the first time, the science underlying climate change. It has said it supports the creation of a carbon tax, which most Republicans have opposed, and it also supported the Paris climate agreement, a major focus of Mr. Kerry’s time in office. Mr. Trump has vowed to abandon the climate pact. In May, Mr. Tillerson told shareholders that “we believe that addressing the risk of climate change is a global issue,” adding that it would require the cooperation of governments, businesses and individuals. (Rex Tillerson, Exxon Chief, Is Expected to be Pick for Secretary of State, Dec. 10, emphasis added)

Missing in this creampuff thumbnail, of course, is #ExxonKnew — the revelations from Inside Climate News and others that Exxon executives suppressed company scientists’ findings in the late 1970s warning of possible catastrophes from the greenhouse effect, and then led a propaganda campaign to block solutions. The editorial also sets an absurdly low bar, in effect giving Tillerson and Exxon credit for “acknowledging” (though not resoundingly endorsing) the scientific consensus on anthropogenic climate change.

Also missing — and the primary subject of this post — are any specifics as to the carbon tax level Exxon supposedly endorses.

A modest carbon tax, say $20 to $40 per ton of carbon dioxide emissions, would aid lower-carbon natural gas in substituting for high-carbon coal, an outcome that would dovetail with Exxon’s gas-heavy but coal-light resource base. Whereas a robust carbon tax, one that would ramp up briskly and reach triple digits within a decade, would not only kayo coal but also deal a heavy blow to oil and gas by giving a big lift to carbon-free renewables and shrinking overall energy demand.

Needless to say, there’s zero evidence that Tillerson or anyone associated with Exxon has ever voiced support for a robust carbon tax.

Indeed, it’s nearly impossible to find even a single Exxon statement specifying the amount of a carbon tax the company would support. This morning we combed a bunch of stories reporting on Exxon’s support for carbon taxing:

• Guardian, Exxon Chief Backs Carbon Tax  Jan. 10, 2009
• Wall Street Journal, Exxon Touts Carbon Tax to Oil Industry, June 30, 2016
• Fortune, Why ExxonMobil Is Supporting a Carbon Tax Now, July 10, 2016
• Dallas Morning News, As Exxon ramps up support of carbon tax, imagine the possibilities, July 6, 2016, editorial
• Dallas Morning News, Exxon proud of its role in climate change dialogue, May 24, 2016, op-ed by Suzanne McCarron, Exxon Mobil v-p of public and government affairs

None of these news stories or opinion pieces mentioned a tax level. To model the Exxon carbon tax shown in our graphic, we went back in time to a 2009 D.C. meeting at which a couple of Exxon “governmental relations” officials sat down with carbon tax advocates. The off-the-record session was short on specifics, but the Exxon reps floated a $20 a ton figure. I’ve raised that to $25, more than capturing seven years of inflation, but have kept the tax level flat in real terms over time.

The graph makes apparent how little such a modest tax would reduce carbon emissions. The “robust” carbon tax shown — modeled after the McDermott carbon tax that would start at $11.34 per ton of CO2 and increase by $11.34/ton annually — would, by 2040, be eliminating 4-5 times as much CO2 from U.S. smokestacks and tailpipes as the “Exxon carbon tax.”

In carbon taxing, as elsewhere, the devil truly is in the details. Exxon’s rebuttal, if we can call it that, is a Dec. 2015 blog post by v-p Ken Cohen, ExxonMobil and the Carbon Tax, which is long on the company’s business practices (it uses a “proxy carbon price” in its planning) but woefully short on actual policy support for carbon taxes, for the very good reason that such support has been effectively non-existent.

U.S. Senator (and climate stalwart) Sheldon Whitehouse (D-RI) said this more pointedly in a Jan. 2017 Washington Post op-ed: “Take no comfort in Tillerson’s statements that climate change is real and that Exxon supports a carbon tax; that message was never delivered to the fossil-fuel industry’s political gun decks and is a perhaps a deliberate false flag.”

But the last word — missing words, actually — goes to Tillerson himself, as shown in this May 2017 tweet from Inside Climate News’ Jack Cushman:

Rex outlined his world view to State Department employees today, and said not one word about global climate change. https://t.co/Tv4UZhI4fG

— John Cushman (@jackcushmanjr) May 3, 2017

Original graphic has been revised to include two different “Exxon carbon taxes.” Model them, or your own, using CTC’s carbon-tax spreadsheet (Excel file).

Last night I spoke at a forum on carbon taxes organized by NYC350. The venue was the Ethical Culture Society building on Manhattan’s Upper West Side. Coming of age politically in the early sixties in a New York suburb, I was greatly influenced by the humanist perspective I heard in weekly radio broadcasts by the society’s leader, Algernon D. Black.

I shared the podium with two prominent climate advocates – renowned climate scientist James Hansen and Cecil Corbin-Mark of WE ACT for Environmental Justice. Here are my remarks.

I want to thank 350NYC and the NYC Grassroots Alliance for convening us and inviting me. Because my time is limited – as it should be, to allow for discussion – let me dive right in.

Since not all of you know me, I brought a display of books I wrote or helped write, along with my contact information.

The Price of Power (1972) was an exposé – the first – of rampant pollution from U.S. fossil-fuel generating stations. Power Plant Cost Escalation (1981) quantified the skyrocketing costs to build nuclear power plants. Then I turned to what we now call livable-streets activism. With books, organizing and direct action and, yes, arrests.

This work had great impact. Less successful, I admit, has been my campaigning over the past decade for congestion pricing to rationalize and improve transportation in New York City, and for carbon taxes nationwide to slash climate-destroying emissions.

I have something heretical to say about the Standing Rock occupation: For all its rightness in asserting the sovereignty of Native Americans and protecting native people’s water, for all its courage in standing up to militarized assault, for all its importance in building the climate movement, and for all its audacity in winning the first big direct-action victory of the Trump Era, yesterday’s stirring triumph by the Standing Rock resistance will do nothing to slow carbon emissions — by itself.

Oil that doesn’t flow to refineries through the Dakota Access Pipeline will instead come from somewhere else – Kuwait or Texas or a hundred other places – to be burned in cars, trucks and planes, as The Onion reminded us last month.

The last part of that Q&A tells us what we need: demand destruction. Massive demand destruction. And key to demand destruction is carbon taxing. Not a token tax, like Exxon or an occasional Republican supports, or says they do; but a robust, briskly rising carbon tax that, over time, will transform the entire economic and social structure that locks people and communities into fossil fuels. A tax that rewards any and every behavior and investment that uses less coal, oil or gas, not more.

A carbon tax of that magnitude will generate enormous revenue – an issue I’ll come back to. But first I want to explain why demand destruction on the scale we need won’t come from other policies and campaigns unless they’re backed by a robust carbon tax.

De-subsidize Fossil Fuels? By all means. But when U.S. taxpayer subsidies to fossil fuels are expressed per gallon, they’re actually pretty small. Most of the IMF’s $5 trillion annual figure for worldwide fuel subsidies is “externalities”: air pollution and especially climate damage. De-subsidizing fossil fuels means taxing them. (More here.)

Clean-Energy Subsidies? They’ve done wonders for renewables. But as wind and solar grow – and they’re on track this year to provide nearly 7 percent of U.S. electricity – subsidizing them is going to get unaffordable. And 7 percent of electricity is only a few percent of energy. Renewables have a long way to go. (More here.)

Efficiency Standards? These are also doing wonders, forcing design changes in appliances, vehicles and buildings that “market forces” alone would not have brought. But these savings too aren’t enough. Standards are reactive, they’re slow and shot through with loopholes. Standards are also piecemeal and scattershot, forever trying to catch up with evolving technology. (More here.)

Most important, standards alone can’t motivate the changes in behavioral patterns that maximize energy savings. Consider mileage (CAFÉ) standards. Yes, they’re valuable, but at best they affect only half of the gasoline-usage equation.

We’re not going to get deep cuts with half-measures. A carbon tax – a robust one – is no half-measure. It’s the one policy that can elicit the billions of carbon-reducing decisions and behaviors that a swift full-scale transition to clean energy requires.

On an individual level, a carbon tax will motivate switches from disposable plastic bottles to refillable ones. Carbon taxes will motivate businesses to produce goods domestically, retaining and growing jobs, as shipping prices rise. Now multiply those examples across the board. Everything will “pencil out” more toward low-carbon and zero-carbon sustainability.

Those changes will add up. The higher the tax, the bigger and faster the reductions. (More here.)

This enormous tantalizing potential is what the Carbon Tax Center fights for. It’s also why the fracturing of the climate movement that contributed to the defeat of the carbon tax referendum last month in Washington State is so distressing.

Because my time is limited, I’ll make just a few points about that campaign.

First, the “sales-tax swap” in the Washington carbon tax – lowering the state sales tax to cushion the bite from the carbon tax – was the only available ironclad way to protect low and moderate-income families from the higher-priced energy. Castigating it as a right-wing “tax cut” was misleading and wrong.

Second, the tax proponents kept the price relatively low – $25/ton though rising over time – because any one state is limited in how it can go. The point of the measure was not to make Washington state carbon-free but to break the national logjam and start a stampede leading to a U.S. carbon tax. And the experience of British Columbia shows that even a modest carbon tax has a noticeable impact.

Third, the “Left Greens” who opposed the Washington initiative because it didn’t invest the revenues in communities never came up with an actual plan to do so. The opponents were also unpersuaded that a carbon tax would cut emissions across-the-board, including in frontline communities. To me, it’s axiomatic that it will.

We have to do better next time. The Keep It In The Ground movement needs to embrace carbon taxes. Not as a “good idea” but as a central demand. And, while we can and should debate details of carbon tax design, including revenue treatment, we need to get behind any and every carbon tax that keeps low and moderate-income families whole.

There aren’t many “next times” left. We need to bring our movements together.

A new report by Harvard economist Joe Aldy is getting some play in climate policy circles. Long-Term Carbon Policy: The Great Swap argues that the incoming administration might support a national carbon tax if it were made part of a deal to lower tax rates and jettison carbon regulations.

Aldy explains:

A smart deal to tackle climate change could abet tax and regulatory reform — which most Republicans support — by swapping a market-based carbon tax for sectoral regulatory policies — which most Republicans oppose. Such an approach could make even greater reductions in tax rates politically feasible and demonstrate that Republicans are in favor of smarter environmental policy, not simply opposed to all climate change policies.

To say we’re skeptical is putting it mildly. Why would a President Trump and an emboldened and still-Republican Congress take on a carbon tax to get stuff (gutted CO2 regs, lower taxes) they can almost certainly win straight up? But rather than point yet again to Republican denialism, we’re inviting you — fellow carbon tax proponents — to address Aldy’s carbon tax rate.

Aldy’s carbon tax would start in 2018 at $25 per ton of CO2 and increase by 5% a year above the rate of general inflation. By 2025, he writes, it would reduce total U.S. carbon emissions by 26 percent.

Is that a lot or a little? A 26 percent reduction would be a lot if it were relative to 2016 emissions, or to 2025 emissions without a carbon tax. Unfortunately, the projected reduction is vis-a-vis levels in 2005 (the year used as a baseline in many climate-policy discussions).

Aldy isn’t perfectly clear on that point. He states in his report:

This carbon tax would lower U.S. carbon dioxide emissions 26 percent by 2025 — consistent with our nation’s pledge at the Paris climate summit last year –and more than 30 percent by 2030.

No 2005 baseline there, though we’re sure Aldy intended it. Clarity is critical because carbon emissions have already fallen a great deal. Compared to 2005, U.S. emissions last year were already 12 percent less, which is nearly half the distance to 26 percent. And emissions are set to fall further this year, as reductions from coal’s continued plunge in the electricity sector outweigh the increase in gas-guzzling caused by cheap gasoline.

Moreover, according to CTC’s carbon-tax model, which perfectly matches Aldy’s estimate of the impact of his carbon tax (our model says the reduction from 2005 would be 25.7 percent), U.S. emissions in 2025 without a carbon tax will be nearly 15 percent below the 2005 baseline. The Aldy carbon tax would cut emissions by only another 13 percent.

Is that a lot or a little? I guess it depends. It’s precious little in an Obama or Clinton world, not to mention a Sanders world. It’s not so small, perhaps, in a Trump world. Still, maybe Aldy — or another expert or advocate — could get more aggressive with the tax rate? The same tax increasing at 10% a year (above inflation) rather than 5% would reduce 2025 emissions by 29% (relative to 2005), with reductions accelerating and reaching 40% by 2033. Why not start the conversation there?

We invite readers to download CTC’s carbon tax model to see for themselves how fast Joe Aldy’s tax, or different ones, would drive down U.S. carbon emissions. Dust off your copy of Excel and click here. Our Web page Carbon Tax Effectiveness goes behind the model curtain to reveal what / why / how.